Mine have been through the wash a couple of times already and are just as effective as they were when I took them out of the package.
You really want to try these, you will love them. You can find them here... https://squareup.com/market/critters-and-creations/kaywos-cloth
Unfortunately, the shopping cart I am using doesn't allow adjustments on the shipping. It is a flat rate for the whole order so I would recommend ordering more than one to help defray the shipping cost. Anything else you might be interested in in my store would also be included in the flat rate shipping as well. Check it out.